Engine mount

ABSTRACT

An engine mount wherein an elastic body connecting upper and lower rigid members has a front-back dimension of its upper half smaller than that of its lower half with the upper half constitutes a front-back direction rubber stopper portion opposed to and spaced apart from a pair of leg portions of a bridge shaped stopper member in the front-back direction by a stopper clearance. The bridge shaped stopper member is press fitted onto the elastic body and the lower rigid member by being assembled through an opening of a lower end thereof, with the lower half clamped elastically between the pair of leg portions. With the stopper member being press fitted onto the elastic body and the lower rigid member, the pressing portions of the stopper member press downwardly the shoulder portions of the elastic body causing compression deformation of the lower half, producing a state of fixation of the lower half to the stopper member.

INCORPORATED BY REFERENCE

The disclosure of Japanese Patent Application No. 2004-253081 filed onAug. 31, 2004, No. 2004-344570 filed on Nov. 29, 2004, and No.2005-054298 filed on Feb. 28, 2005, each including the specification,drawings and abstract is incorporated herein by reference in itsentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an engine mount for supporting an engine on avehicle body in a vibration damping fashion, and in particular to anengine mount of a configuration which comprises a stopper member that isa rigid member of bridge shaped, and which provides vibration-dampingsupport of the engine in a suspension manner.

2. Description of the Related Art

Various types of engine mounts that providing vibration-damping supportof an engine have been employed. One type is of a configuration whichcomprises a bridge shaped stopper metal member (rigid stopper member),and which provides vibration-damping support of the engine in asuspension manner.

JP-A-5-18428, JP-A-8-233010 and JP-A-8-296681 disclose engine mountsfurnished with bridge-type metal members. However, the designs disclosedin these documents differ in object from the present invention in thatthey lack an arrangement wherein the upper half of the rubber elasticbody constitutes a stopper portion in the front-back direction, and inthat the bridge-type metal member is not constituted as a stopper metalmember that restricts front-back displacement through cooperative actionwith the rubber stopper portion.

SUMMARY OF THE INVENTION

Present inventors has originally made several prototypes of an enginesuspension type engine mount. FIGS. 7A and 7B show, by way of acomparative example II, an engine suspension type engine mount with abridge shaped stopper metal member of this kind, produced as a prototypeby the inventors. In the drawing, symbol 200 denotes an upper metalmember (upper rigid member) affixed to the engine side, 204 denotes alower metal member (lower rigid member) affixed to the vehicle bodyside, and 206 denotes a rubber elastic body integrally fixed to these bymeans of vulcanization bonding, linking the two together.

As shown in FIG. 8, the upper metal member 200 has integrallyconstituted therewith a bracket metal member (rigid bracket) 201 thatextends in the same axial direction from a first axial end thereof, forlinking the upper metal member 200 to the engine side. The engine issecured fastened to the end of this bracket 201 so as to be supported ina suspended configuration.

The rubber elastic body 206 has a front-back dimension of its upper half210 that is smaller than the front-back (corresponding to the right-leftdirection in the drawing) dimension of its lower half 208, with rubberstopper portions 212 being formed in the front-back direction by thisupper half 210. 214 denotes a bridge shaped stopper metal member havinga pair of leg portions 216 situated at front and back, and a bridgeportion 218 that connects the pair of leg portions 216 at the top of therubber elastic body 206.

With this engine mount 202, the bridge shaped stopper metal member 214is pushed downwardly in the drawing, press metal member the rubberelastic body 206 into it through the opening at the bottom of thestopper metal member 214, and attached thereby to the rubber elasticbody 206 and the lower metal member 204 with the lower half 208 of therubber elastic body 206 clamped elastically between the pair of legportions 216. More specifically, the inner faces 220 of the press fitpair of leg members are disposed in elastic pressing contact with frontand back contact faces 222 of the lower half 208 in the rubber elasticbody 206, and in this state a fastener portion 224 at the bottom end ofeach leg portion 216 is fastened to a fastener portion 226 on the lowermetal member 204, whereby the bridge shaped stopper metal member 214 isattached to the rubber elastic body 206 and the lower metal member 204.

This assembled state is depicted in FIG. 7B. The rubber stopper portions212 in the front-back direction of the upper half 210 in the rubberelastic body 206 is situated in opposition to the pair of leg portions216 of the stopper metal member 214 and spaced apart therefrom in thefront-back direction by stopper clearance. These rubber stopper portions212 come into abutment with the leg portions 216 to produce stopperaction when the engine experiences appreciable relative displacement inthe front-back direction, restricting excessive front-back displacementof the engine.

This engine mount 202 is mounted elastically supporting the left-rightedge (specifically, the edge on the left side) of the engine, andtogether with other engine mounts elastically supports the engine, andprovides vibrational isolation between the engine side and the vehiclebody side by means of elastic deformation of the rubber elastic body206.

In this engine mount 202, the inner faces 220 of the leg portions 216 ofthe bridge shaped stopper metal member 214 and the front/back contactfaces 222 of the lower half 208 of the rubber elastic body 206 aresimply in elastic pressure-contact, without being adhered to each other.On the other hand, there is an inherent characteristic problem in thatsince the engine is supported in a suspension system, and since moreoverthe bracket metal member 201 extends integrally in the axial directionfrom the upper metal member 200 of the engine mount 202 so as to besupported in cantilever fashion by the rubber elastic body 206, when theengine gives rise to relative motion in pitching mode, i.e. when theleft/right edges of the engine undergo vertical motion in opposite phaseso that the engine overall gives rise to rocking motion, the bracket 201integrally constituted with the upper metal member 200 as shown in FIG.8 will undergo appreciable rotary motion in the vertical direction inthe drawing. Therefore, the front/back contact faces 222 of the lowerhalf 208 of the rubber elastic body 206 will undergo rubbing motionagainst the inner faces 220 of the leg portions 216 of the bridge shapedstopper metal member 214, whereby the rubber elastic body 206 willbecome abraded by the contact faces 222, and noise will tend to beproduced by rubbing at this time.

It is therefore an object of the present invention to provide an enginemount wherein an upper half of a rubber elastic body constitutes arubber stopper portion in a front-back direction, and which is capableof suppressing abrasion due to rubbing, and preventing noise produced bysuch rubbing, occurring at contact faces between an lower half of therubber elastic body and a bridge shaped rigid stopper member.

Mode 1 of the invention provides an engine mount for a vehiclecomprising: an upper rigid member fixable to an engine side; a lowerrigid member fixable to an vehicle body side; a rubber elastic bodyelastically connecting the upper and lower rigid members; and a rigidstopper member of overall bridge configuration having a pair of legportions situated at front and back and a bridge portion linking theseleg portions in a front-back direction of the vehicle above the rubberelastic body, wherein the rubber elastic body has a front-back dimensionof an upper half thereof smaller than that of a lower half thereof; theupper half constitutes a front-back direction rubber stopper portionopposed to and spaced apart from the pair of leg portions of the bridgeshaped stopper member in the front-back direction by a stopperclearance; the bridge shaped stopper member is press fitted onto andattached to the rubber elastic body and the lower rigid member by beingassembled through an opening of a lower end thereof, with the lower halfclamped elastically between the pair of leg portions; a rigid bracketfor linking the upper rigid member to the engine side is integrallyformed on the upper rigid member, with the rubber elastic bodysupporting the bracket in a cantilever fashion so that the enginesecured fastened to the bracket being supported in a suspension fashion;the upper rigid member and the lower rigid member are integrallyvulcanization bonded to the rubber elastic body; a pair of shoulderportions of step configuration projecting in the front-back directionfrom an upper end of the lower half are disposed at front and back onthe rubber elastic body, while downturned pressing portions of stepconfiguration are disposed at corresponding front and back locations onthe bridge shaped stopper member; and with the stopper member beingpress fitted onto the rubber elastic body and the lower rigid member,the pressing portions of the stopper member press downwardly theshoulder portions of the rubber elastic body causing compressiondeformation of the lower half, producing a state of fixation of thelower half to the stopper member.

Mode 2 of the invention provides an engine mount according to theaforementioned Mode 1, wherein each of the shoulder portion has a shapeprior to attachment of the stopper member, in which a portion thatcontacts the pressing portion includes an upwardly projecting convexportion at an outer portion thereof in the front-back direction, and arelatively downward facing concave portion at an inner portion thereof.

Mode 3 of the invention provides an engine mount according to theaforementioned Mode 2, wherein the pressing portion has a shape thatpresses the upwardly projecting convex portion until the convex portionis rendered non-convex by means of attachment.

Mode 4 of the invention provides an engine mount according to any of theaforementioned Modes 1-3, wherein each of the shoulder portions isformed over an entirety of a width direction of the rubber elastic bodywhich is a left-right direction of the vehicle, and each of the pressingportions is formed as a pair of pressing portions located at oppositeends in the width direction of the stopper member, with a portion lyingbetween the pair of pressing portions at the opposite ends in the widthdirection being constituted as a reinforcing rib.

Mode 5 of the invention provides an engine mount according to any one ofthe aforementioned Modes 1-4, wherein in the rubber elastic body,portions extending from front and back stopper faces down to front andback contact faces of the lower half against the stopper member arecontinuous with contact faces without creating a constricted portion inthe front-back direction at midpoint.

Mode 6 of the invention provides an engine mount according to any one ofthe aforementioned Modes 1-5, wherein portions of the lower rigid memberthat are opposed vertically to the pressing portions are formed asupturned convex portions.

Mode 7 of the invention provides an engine mount according to theaforementioned Mode 6, wherein each of the upturned convex portions ofthe lower rigid member includes in an outside of a vertex thereof in thefront-back direction, a pressure surface extending towards an insidesurface of the leg portion opposed thereto as it goes downward, and thecorresponding shoulder portion of the rubber elastic body 16 isconfigured so as to extend toward the inside surface of thecorresponding leg portion beyond the vertex.

Mode 8 of the invention provides an engine mount according to theaforementioned Mode 7, wherein the shoulder portions of the rubberelastic body have the upturned convex portions at their most outerperipheral edge portions in the front-back direction.

Mode 9 is an engine mount according to any one of the aforementionedModes 6-8 wherein the convex portions of the lower rigid member areembedded within the interior of the lower half of the rubber elasticbody, and exert restraining action from an interior of the rubberelastic body against portions of the lower half clamped by the stoppermember.

Mode 10 is an engine mount according to the aforementioned Mode 9,wherein the convex portions of the lower rigid member have straightshaped portions that rise straight along the leg portions in the bridgeshaped stopper member, with thin rubber layers constituting part of therubber elastic body being formed between the straight shaped portionsand the leg portions, respectively.

Mode 11 is an engine mount according to any one of the aforementionedModes 1-10, wherein an entire fastener portion to the rubber elasticbody of the lower rigid member is embedded within the rubber elasticbody, with a rubber underlayer constituting part of the rubber elasticbody being formed below the lower rigid member.

OPERATIONS AND EFFECTS OF THE INVENTION

In the present invention as described hereinabove, the pair of shoulderportions of step configuration projecting in the front-back directionare disposed at the upper end of the lower half of the rubber elasticbody, while a downturned pair of pressing portions of step configurationare disposed at corresponding front and back locations on the bridgeshaped stopper member. When attaching the stopper member by means ofpress fitting, the shoulder portions of the rubber elastic body arepushed downwardly by the pressing portions, producing a state offixation of the lower half to the rubber elastic body to the stoppermember.

According to the present invention, even in the case where the enginemount is an engine mount that supports the engine in a suspensionfashion, that is, one in which, due to left/right rocking motion of theengine in pitching mode, and additionally due to the bracket beingintegrally constituted in the cantilever fashion on the upper rigidmember, the bracket undergoes appreciable rotary motion in the verticaldirection, and a high level of force acts so as to produce relativemotion (motion in the vehicle left-right direction) of the lower half ofthe rubber elastic body and the bridge shaped stopper member, andadditionally the rubber elastic body has not been adhered to the bridgeshaped stopper member, it is nevertheless possible, by means of thefastening action of the pressing portions, to suppress the occurrence ofthe contact faces of the lower half of the rubber elastic body rubbingagainst the stopper member during motion of the engine, in particular,principally the aforementioned left-right rocking motion in pitchingmode, and to thereby better prevent abrasion of the rubber elastic bodydue to such rubbing, as well as to effectively prevent noise produced bysuch rubbing. Additionally, with the present invention, the lower rigidmember together with the upper rigid member is integrally vulcanizationbonded to the rubber elastic body, affording strong anchoring force ofthe lower rigid member to the lower half of the rubber elastic body, andthereby better preventing abrasion of the contact faces of the rubberelastic body and noise produced by such rubbing.

On the other hand, with this engine mount, the upper half in the rubberelastic body, more specifically the front-back direction rubber stopperportions formed in the upper half thereof, is opposed to the bridgeshaped stopper member in a non-contacting state spaced apart therefromby stopper clearance. Therefore, when the engine undergoes appreciablerelative displacement in the front-back direction, maximum displacementcan be better restricted by means of the stopper action of the rubberstopper portions. Additionally, with the present invention, by means ofvarying the compressive deformation allowance of the rubber elasticbody, i.e. the pre-compression level, by the pressing portion of thestopper member, it is possible to variously modify and adjust the springconstant of the rubber elastic body, which has the advantage of greaterfreedom in tuning the spring constant of the engine mount.

Next, Mode 2 is the engine mount wherein the shape of the shoulderportion, more specifically the shape of the shoulder portion prior toattachment of the stopper member, is one in which, of the portion thatcontacts the pressing portion, the outer portion thereof in thefront-back direction constitutes an upwardly projecting convex portion,and the inner portion thereof constitutes a relatively downward facingconcave portion.

Where the shape of the shoulder portion is one that, for example,contacts the pressing portions of the stopper member with equal force atall points, relative displacement of the engine during use will beaccompanied by concentrations of stress in border regions betweenportions contacted by the pressing portions and portions not contacted,and cracks can occur from these sites, thus creating the problem ofdiminished durability of the engine mount. Nevertheless, with Mode 2,since the outer portion in the front-back direction constitutes theupward facing convex portion, and the inner portion constitutes thedownward facing concave portion, even where the shoulder portions of therubber elastic body are in the downwardly pressed state due toattachment of the stopper member, concentrations of stress in theaforementioned border regions can be better avoided. Accordingly theproblem of cracks occurring from these border regions and diminishingthe durability of the engine mount can be better resolved, so that thedurability of the rubber elastic body, i.e. of the engine mount, can bemade better.

The aforementioned pressing portion can be given a shape that pressesthe convex portion and induces elastic compressive deformation, untilthe convex portion prior to assembly is rendered non-convex by means ofattachment (Mode 3).

Next, according to Mode 4, the aforementioned shoulder portions can beformed over the entirety of the width direction (vehicle left-rightdirection) of the rubber elastic body on the one hand, while thepressing portions are disposed partially at each end in the widthdirection of the stopper member, with portions in the width directionbetween the pressing portions being constituted as reinforcing ribs. Byso doing, reduced strength in the front-back direction of the stoppermember due to formation of the pressing portions is prevented by thereinforcing ribs, and rigidity and strength of the stopper member in thefront-back direction can be maintained at high levels of rigidity andstrength.

In the present invention, portions of the rubber elastic body extendingfrom the front and back stopper faces down to the contact faces of thelower half against the stopper member can be constituted as surfacesthat are continuous with the contact faces, without creating aconstricted portion in the front-back direction at midpoint (Mode 5).

Next, Mode 6 is an engine mount wherein portions of the aforementionedlower rigid member that are opposed vertically to the pressing portionsin the stopper member are upturned convex portions. Thus, according tothis Mode 6, the front end and the back end of the lower half in therubber elastic body can be fastened more securely by means of thepressing portions of the stopper and the convex portions of the lowerrigid member, and rubbing of the stopper member of the rubber elasticbody against the contact faces can be effectively suppressed. Theupturned convex portions of this lower rigid member also have the actionof producing a stiffer spring constant of the rubber elastic body, andthus there is the additional advantage that by varying the projectionheight of the convex portions, the tuning range of the spring constantof the rubber elastic body is expanded.

Next, Mode 7 is an engine mount wherein each of the upturned convexportions of the lower rigid member includes in an outside of a vertexthereof in the front-back direction, a pressure surface extendingtowards an inside surface of the leg portion opposed thereto as it goesdownward, and the corresponding shoulder portion of the rubber elasticbody 16 is configured so as to extend toward the inside surface of thecorresponding leg portion beyond the vertex. With this arrangement, whenassembling the bridge shaped stopper member in order to press downwardthe rubber elastic body (more specifically, the lower half), the part ofthe rubber elastic body undergoing compression elastic deformation ispressed toward the inside surface sides of the leg portions due to thepressure surfaces of the upturned convex portions. This arrangementmakes it possible to increase a frictional force generated between thecontact surfaces of the rubber elastic body and the inside surfaces ofthe leg portions, resulting in increased bonding and fastening forces.

The part of the rubber elastic body pressed out by means of the functionof the rubber are pre-compressed between the inside surfaces of the legportions and the upturned convex portions, so that the deformationcaused by means of the rocking motion of the bracket can be effectivelyabsorbed. This as well as the increased bonding and fastening forcesfurther effectively prevent rubbing of the contact surfaces of the lowerhalf in the rubber elastic body and the inside surfaces of the legportions, whereby rubbing of the lower half in the rubber elastic bodyand noise resulting from this can be more effectively prevented.

In the case of Mode 8, the shoulder portions of the rubber elastic bodyhave the upturned convex portions at their most outer peripheral edgeportions in the front-back direction. Therefore, when the pressureportions press the shoulder portions downwards, the downward compressionelastic deformation of the convex portions at the outer peripheral edgeportions of the shoulder portions promptly converted into compressionforce in the front-back direction against the inside surfaces of the legportions of the stopper member. Therefore, the frictional forcegenerated between the contact surfaces of the rubber elastic body andthe inside surfaces of the leg portions can be increased, andaccordingly the resultant bonding force as well as the pre-compressioncan be created effectively. Thus, rubbing of the lower half in therubber elastic body and noise resulting from this can be moreeffectively prevented, furthermore.

In this case of Mode 9, the convex portions of the lower rigid memberare embedded within the interior of the lower half of the rubber elasticbody, and exert restraining action from an interior of the rubberelastic body against portions of the lower half clamped by the stoppermember. By so doing, rubbing of the lower half in the rubber elasticbody and noise resulting from this can be more effectively prevented.

In this case, the convex portion of the lower rigid member may have thestraight shaped portion that rises straight along the leg portion in thebridge shaped stopper member, with a thin rubber layer constituting partof the rubber elastic body being formed between the straight shapedportion and the leg portion (Mode 10). In this case, the lower half ofthe rubber elastic body in the portion where the straight shaped portionis formed is held between the straight shaped portion and the legportion, at uniform thickness over a predetermined distance in thevertical direction, whereby the desired interference can be readilyassured when press metal member the rubber elastic body into the bridgeshaped stopper member.

Next, Mode 11 is an engine mount, wherein the entire fastener portion ofthe lower rigid member to the rubber elastic body is embedded in theinterior thereof, with a rubber underlayer constituting part of therubber elastic body being formed below the lower rigid member. Accordingto Mode 11, when the lower rigid member is constituted by a metal memberwhich is integrally vulcanization bonded to the rubber elastic bodyduring vulcanization molding, it is not necessary to give the formingmold a cut structure for the lower rigid member, whereby the design ofthe forming mold and the structure of the engine mount may besimplified, as well as solving the problem of rubber flash at the end ofthe lower rigid member; further, the labor entailed in a separateanticorrosive coating process on the bottom face of the lower rigidmember (lower face of the portion embedded in the rubber elastic body)may be avoided.

BRIEF DESCRIPTION OF THE DRAWINGS

The forgoing and/or other objects features and advantages of theinvention will become more apparent from the following description of apreferred embodiment with reference to the accompanying drawings inwhich like reference numerals designate like elements and wherein:

FIG. 1 is a perspective elevational view of an engine mount ofconstruction according to a first embodiment of the invention;

FIG. 2 is a vertical or axial cross sectional view of the engine mountof FIG. 1;

FIG. 3 is an exploded perspective view of a stopper member and a rubberelastic body of the engine mount of FIG. 1;

FIG. 4 is a schematic view showing a state where the engine mount ofFIG. 1 is installed on a vehicle;

FIGS. 5A and 5B are illustrations for explaining steps of assembly ofthe engine mount of FIG. 1;

FIGS. 6A and 6B are views of a comparative example I for explainingadvantages of the present invention;

FIG. 7A and 7B are views of a comparative example II for explainingadvantages of the present invention; and

FIG. 8 is a illustration for explaining a problem in the comparativeexample II.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The embodiment of the invention will be described in detail hereinbelow,with reference to the drawings. In FIGS. 1, 3 and 4, 10 denotes anengine mount for a vehicle according to the embodiment, which has anupper metal member (upper rigid member) 12 fastened to an engine side, alower metal member (lower rigid member) 14 fastened to a vehicle bodyside, a rubber elastic body 16 connecting these, and a bridge shapedstopper metal member (rigid stopper member) 18 constituted as a separateelement from the above. The rubber elastic body 16 is integrally bondedby vulcanization to the upper and lower metal members 12, 14 duringvulcanization molding thereof.

The bridge shaped stopper metal member 18 has a pair of front and backleg portions 20, and a bridge portion 22 linking the pair of legportions 20 in a front-back direction of the vehicle. As shown in FIGS.1 and 3, the stopper metal member 18 is provided with reinforcing ribs24 at both ends in the vehicle left-right direction (perpendicular tothe plane of the paper in FIG. 2). A fastener portion 26 is disposed ateach bottom end of the pair of leg portions. These fastener portions 26are designed to be fasten to corresponding fastener portions 28 of thelower metal member 14.

The aforementioned upper metal member 12 is a hollow tube of rectangularcross section in the portion thereof that fastens to the rubber elasticbody 16, and is affixed to the rubber elastic body 16 by means ofvulcanization bonding while embedded entirely within the rubber elasticbody 16.

As shown in FIGS. 1, 3 and 4, a bracket 30 for fastening to the engine(specifically the transmission) 96 side is integrally constitutedprojecting leftward in the drawings from the upper metal member 12, thebracket 30 being supported in cantilever fashion on the rubber elasticbody 16. In FIG. 4, symbol 90 denotes the vehicle body, 92 denotes abracket on the engine 96 side, and 94 denotes a bracket on the vehiclebody side, for fastening the engine mount 10 to the vehicle body 90.That is, this engine mount 10 is a left engine mount situated on theleft side of the engine 96 and providing vibration damping support tothe edge on the left side of the engine 96 (specifically thetransmission integrally constituted with the engine 96).

As shown in FIG. 1, the bracket 30 is of flatted tube shape overallhaving an upper panel 32, a lower panel 34, and a side wall 36.Through-holes 38 are formed at three locations in the upper panel 32,and through-holes 38 concentric therewith are formed in the lower panel34 as well. On the upper face of the lower panel 34, a nut 40 positionedconcentrically with the through-holes 38 are affixed by means of welding(see FIG. 2). This nut 40 is used for fastening to the engine 96 side.

The rubber elastic body 16 has a front/back pair of rubber legs 41 forsupporting the load of the engine 96. The front-back dimension of anupper half 44 of the rubber elastic body 16 is smaller than thefront-back dimension of a lower half 42 of the rubber elastic body 16,with the front and back portions of the upper half 44 thereof withrespect to the upper metal member 12 constituting front-back directionrubber stopper portions 46 situated opposed to leg portions 20 of thebridge shaped stopper metal member 18, and spaced apart therefrom bystopper clearance C. These stopper faces are denoted by 46A in thedrawing. These rubber stopper portions 46 come into abutment with insidesurfaces 49 of the leg portions 20 of the stopper metal member 18 toproduce stopper action when the engine 96 undergoes appreciabledisplacement in the front-back direction, thereby restricting excessivedisplacement of the engine 96.

On the other hand the front and back faces of the lower half 42constitute contact faces 48 with the stopper metal member 18, thesecontact faces 48 coming into elastic pressing contact with the insidesurfaces 49 of the leg portions 20. That is, the rubber elastic body 16is elastically clamped in the front-back direction in its lower half 42by the front/back pair of leg portions 20 of the bridge shaped stoppermetal member 18.

In the rubber elastic body 16 in the embodiment, with the stopper metalmember 18 having been attached, portions extending from the front andback stopper faces 46A of the rubber stopper portions 46 down to thecontact faces 48 of the lower half 42 extend in the front and backdirections moving downward and are continuous with the contact faces 48,without creating a constricted portion in the front-back direction atmidpoint.

A lightening portion (recess) 50 passing through the center portion isformed in this rubber elastic body 16. On the bottom of this lighteningportion 50, there is formed a rubber stopper portion 52 that produces astopper action during bound. On the upper side of the upper metal member12, there is formed a rubber stopper portion 54 that comes into abutmentwith the bridge portion 22 of the stopper metal member 18 to produce astopper action during rebound.

As shown in FIGS. 3, 5A and 5B, a pair of shoulder portions 56 of stepconfiguration projecting in the front-back direction (left-rightdirection in the drawings) are disposed at front and back at an upperend of the lower half 42 of the rubber elastic body 16. A pair ofdownturned pressing portions 58 of step configuration are disposed atcorresponding front and back locations on the bridge shaped stoppermetal member 18. With the stopper metal member 18 attached, the shoulderportions 56 are pressed downwardly by the pressing portions 58 inassociation with compressive elastic deformation of the lower half 42.By means of this pressing force, the lower half 42, specifically, thefront and back ends, are securely fastened with respect to the lowermetal member 14 and the bridge shaped stopper metal member 18.

As shown in FIG. 3, the pressing portions 58 are disposed respectivelyat front and back, and further are disposed at each end of the stoppermetal member 18 in its width direction (vehicle left-right direction).The portion between these pressing portions 58 and 58 in the widthdirection is constituted as a reinforcing rib 70 of sloping shape (seeFIG. 1). As shown in FIG. 5A, the aforementioned shoulder portion 56, inthe shape thereof prior to attachment of the stopper metal member 18, ofa portion that contacts the pressing portion 58, an outer portionthereof in the front-back direction forms an upwardly projecting convexportion 60, and an inner portion continuous therewith forms a concaveportion 62 with a relatively downward facing bowed shape. The upwardlyprojecting convex portion 60 is disposed on the shoulder portion 56 at amost outer peripheral edge portion thereof in the front-back direction.

Accordingly, the upwardly-directed pressing force of the pressingportions 58 is applied primarily to the convex portion 60. The convexportion 60 undergoes elastic deformation due to this pressing force, andin association therewith the rubber of the convex portion 60 isdisplaced over into the concave portion 62. The convex portion 60 andthe concave portion 62 are formed continuously over their entire widthwith uniform height and depth in the width direction of the rubberelastic body 16. The pressing portion 58 has a shape that, onceassembled, presses the convex portion 60 downwardly until it is renderednon-convex. The pressing portion 58 has a bowed portion (roundedportion) 72 that bows in the same direction as the convex portion 60,and a bowed portion (rounded portion) 74 that bows in the oppositedirection.

As shown in FIG. 2, the aforementioned lower metal member 14 is disposedwith the fastener portion 28 for fastening to the rubber elastic body 16embedded within the rubber elastic body 16, and with the front end andback end thereof, specifically the portions opposed in the verticaldirection to the pressing portions 58 in the stopper metal member 18,constitute upturned convex portions 64. The upturned convex portion 64has a straight shaped portion 64A that rises straight upwardly along theleg portion 20 in the stopper metal member 18, an inflection portion 64Bthat bows at the upper edge and inflects downward, and a sloping portion64C continuous therewith and having a sloping shape.

The inflection portion 64B has an arcuate pressure surface 78 thatextends from its vertex towards the inside surface 49 of thecorresponding leg portion 20 while extending downwardly. Upon assemblingthe stopper metal member 18, this pressure surface 78 function to pressthe rubber elastic body 16 toward the inside surface 49 side of the legportion 20. In this arrangement, the shoulder portion 56 of the rubberelastic body 16 extends outward of the vertex of the inflection portion64B in the front-back direction, i.e., extends towards the correspondingleg portion. As will be understood from FIG. 5A, the convex portion 60of the shoulder portion 56 is disposed outward of the inflection portion64B, i.e., is positioned more closer to the corresponding leg portion 20than the inflection portion 64B.

The straight shaped portion 64A has a thin rubber layer 76 constitutingpart of the rubber elastic body 16 formed between it and the leg portion20. The aforementioned convex portion 64, particularly the slopingportion 64C thereof, has the function of giving stiffer springcharacteristics in the vertical direction of the rubber elastic body 16.

A rubber underlayer 66 is formed in the lower portion thereof. Thisrubber underlayer 66 constitutes part of the rubber elastic body 16, andis integrally joined with the upper portion of the lower metal member14. The lower metal member 14 is covered on the left and right end facesthereof perpendicular to the plane of the paper in FIG. 2 by the rubberelastic body 16.

As shown in FIG. 5A, in the engine mount 10 of this embodiment, thebridge shaped stopper metal member 18 is positioned above the rubberelastic body 16, and pushed in downwardly in the drawing to attach thestopper metal member 18 to the rubber elastic body 16 and the lowermetal member 14. More specifically, when the stopper metal member 18 ispushed in downwardly, the rubber elastic body 16 becomes press fit intothe stopper metal member 18 through an opening in the bottom end, andthe fastener portions 26 of the pair of lower ends of the stopper metalmember 18 are then fastened to the fastener portions 28 of the lowermetal member 14, attaching the bridge shaped stopper metal member 18 tothe rubber elastic body 16 and the lower metal member 14.

At this time, the lower half 42 of the rubber elastic body 16 iselastically clamped in the front-back direction by the pair of legportions 20 of the stopper metal member 18, and the contact faces 48 atfront and back of the lower half 42 are disposed in elastic pressingcontact against the inside surfaces 49 of the leg portions 20 of thestopper metal member 18.

Further, the pressing portions 58 of the stopper metal member 18 exertdownward pressing force against the shoulder portions 56 of the lowerhalf 42, and by means of the pressing force of the pressing portions 58,the front and back ends of the lower half 42 are fastened to the stoppermetal member 18, in a state of elastic compressive deformation in thevertical direction.

At this time, the front and back ends of the lower half 42 are clampedin the vertical direction by the pressing portions 58 and the lowermetal member 14, affording strong anchoring force.

In the embodiment as described above, the shoulder portions 56 aredisposed on the lower half 42 of the rubber elastic body 16, and theseare pressed by corresponding pressing portions 58 provided on the bridgeshaped stopper metal member 18, securely fastening the lower half 42,whereby in the engine mount 10 that provides vibration-damping supportof an engine 96 in a suspension system, in which, due to left/rightrocking motion of the engine 96 in pitching mode. Additionally due tothe bracket 30 being integrally constituted in a cantilever fashion onthe upper metal member 12, the bracket 30 undergoes appreciable rotarymotion in the vertical direction, and a high level of force acts so asto produce relative motion in the vehicle left-right direction of thelower half 42 of the rubber elastic body 16 and the stopper metal member18, it is nevertheless possible to suppress the rubbing of the contactfaces 48 of the lower half 42 against the stopper metal member 18, andto thereby better prevent abrasion of the rubber elastic body 16 due tosuch rubbing, as well as the noise produced by such rubbing.

In this embodiment, the upper metal member 12 and the lower metal member14 are bonded by vulcanization to the rubber elastic body 16, and theanchoring force of the lower metal member 14 to the lower half 42 of therubber elastic body 16 is strong. Thus, rubbing of the contact faces 48of the rubber elastic body 16 and the noise produced by this rubbing canbe better prevented.

In this embodiment, since the outer portion in the front-back directionof the shoulder portion 56 constitutes the convex portion 60 and theinner portion constitutes the concave portion 62, even where theshoulder portions 56 of the rubber elastic body 16 are in a state ofbeing pressed downwardly by means of attaching the stopper metal member18, concentrations of stress in the border regions can be avoided. Theproblem of cracks occurring from these regions and diminishingdurability can be effectively solved.

Specifically, as shown in a comparative example I diagram of FIGS. 6Aand 6B, where the shape of a shoulder portion 56A is a shape thatcontacts the pressing portion 58 of the stopper metal member 18 withequal force at all points, relative displacement of the engine 96 duringuse will be accompanied by concentrations of stress being produced inborder regions between the portion contacted by the pressing portionsand the portion not contacted, and cracks can occur from these sites,thus creating the problem of diminished durability of the engine mount10. Nevertheless, with this embodiment, since the shape of the shoulderportion 56 has the shape described hereinabove, concentrations of stressin specific regions can be better avoided, and better durability of theengine mount 10 achieved.

Further, the shoulder portions 56 are formed along its entire widthdirection (vehicle left-right direction) of the rubber elastic body 16,whereas the pressing portions 58 are disposed partially at each end inthe width direction of the stopper metal member 18, with portions lyingbetween the pressing portions 58 at the ends in the width directionbeing constituted as reinforcing ribs 70. Therefore, diminished strengthof the stopper metal member 18 in the front-back direction due toformation of the pressing portions 58 may be prevented, and rigidity andstrength of the stopper member in the front-back direction can bemaintained at high levels of rigidity and strength.

In this embodiment, the portions of the lower metal member 14 opposed inthe vertical direction to the pressing portions 58 in the stopper metalmember 18 are constituted as upturned convex portions 64. Therefore, thefront end and the back end of the lower half 42 in the rubber elasticbody 16 can be fastened more securely by means of the pressing portions58 of the stopper metal member 18 and the convex portions 64 of thelower metal member 14. Also, rubbing of the stopper metal member 18 ofthe rubber elastic body 16 against the contact faces 48 can beeffectively suppressed. The upturned convex portions 64 of this lowermetal member 14 also have the action of producing a stiffer springconstant of the rubber elastic body 16. Thus, there is the additionaladvantage that by varying the projection height of the convex portions64, the tuning range of the spring constant of the rubber elastic body16 is expanded.

According to this embodiment, the pressure surface 78 of arcuate shape(or alternatively inclined shape) is formed in the upturned convexportion 64 of the lower metal member 14, while the shoulder portion 56of the rubber elastic body 16 is configured so as to extend toward theinside surface 49 of the corresponding leg portion 20 beyond the vertexof the inflection portion 64B. With this arrangement, when the stoppermetal member 18 is assembled, and the shoulder portion 56 of the rubberelastic body 16 undergoes compression elastic deformation in downwarddirection by means of the pressing portions 58, a portion of the rubberelastic body 16 under compression deformation is forcedly pressed bymeans of the pressure surface 78 toward the inside surface 49 of the legportion 20. Thus, the rubber elastic body 16 can be forcedly pressfitted against the inside surface 49 of the front and back leg portions20, 20. With this arrangement, the rubber elastic body 16, morespecifically the lower half 42 of the rubber elastic body 16 can berestricted with a greatly increased force, and thus fastened to the legportions 20, 20 with great fastening force.

The portion of the rubber elastic body 16, which is pressed outwardly bymeans of the pressure surface 78, is held in a compressed state betweenthe inside surface 49 of the leg portion 20 in the front-back direction.Therefore, if the bracket 30 moves in a vertical direction, this motioncan be efficiently absorbed by means of this advance compression of therubber elastic body 16. This advantage, together with the aforementionedincrease of the fastening force, makes it possible to furthereffectively restrict rubbing between the contact face 48 of the rubberelastic body 16 and the inside surface 49 of the corresponding legportion 20. Thus, further effectively prevented is occurrence ofabrasion of the rubber elastic body 16 due to such rubbing, as well asthe noise produced by such rubbing.

In addition, the upwardly projecting convex portion 60 is disposed onthe shoulder portion 56 at the most outer peripheral edge portionthereof in the front-back direction. Therefore, when the upwardlyprojecting convex portions 60 are forcedly pressed downwardly by meansof the pressing portions 58, the created compression elasticdeformational force is promptly converted into the compression forcetoward the inside surface 49 of the front and back leg portions 20, 20in the front-back direction. With this arrangement, the frictional forcegenerated between the contact faces 48 and the inside surfaces 49 willbe enhanced, thereby generating increased fixing force therebetween.Also, the pre-compression force will also be enhanced, therebyeffectively preventing abrasion of the rubber elastic body 16 due tosuch rubbing, as well as the noise produced by such rubbing.

Since the convex portions 64 of the lower metal member 14 are embeddedwithin an interior of the lower half 42 of the rubber elastic body 16,and exert restraining action from within on the portion of the lowerhalf 42 which is clamped by the stopper metal member 18, rubbing of thelower half 42 in the rubber elastic body 16 and noise resulting fromthis can be more effectively prevented.

In this case, the convex portion 64 of the lower metal member 14 has thestraight shaped portion 64A that rises straight along the leg portion 20in the bridge shaped stopper metal member 18. Therefore, with the thinrubber layer 76 constituting part of the rubber elastic body 16 beingformed between the straight shaped portion 64A and the leg portion 20,the lower half 42 of the rubber elastic body 16 is held between thestraight shaped portion 64A and the leg portion 20 at uniform thicknessover a predetermined distance in the vertical direction, whereby thedesired interference can be readily assured when attaching the rubberelastic body 16 by press metal member into the bridge shaped stoppermetal member 18.

Further, an entire fastener portion 28 of the lower metal member 14 tothe rubber elastic body 16 is embedded in an interior of the rubberelastic body 16. Therefore, with the rubber underlayer 66 constitutingpart of the rubber elastic body 16 being formed therebelow, at the timeof integral vulcanization bonding of the lower metal member 14 to therubber elastic body 16 during vulcanization molding, it is not necessaryto give the forming mold a cut structure for the lower metal member 14.Thus, the design of the forming mold and the structure of the enginemount 10 may be simplified, as well as solving the problem of rubberflash at the end of the lower metal member 14. Further, the laborentailed in performing a separate anticorrosive coating process on thebottom face of the lower metal member 14 may be avoided.

In the engine mount 10 of the embodiment, by means of appropriateselection of the locations of the shoulder portions 56 and the pressingportions 58, the level of compressive deformation applied to the lowerhalf 42 can be appropriately modified and adjusted. Thus, it is possibleto variously adjust the spring constant of the rubber elastic body 16,i.e. of the engine mount 10. Table 1 gives an example of vertical andfront-back spring constants in the case where the aforementionedshoulder portions 56 and the pressing portions 58 are provided, and inthe case where they are not; as will be apparent from the table, springconstant in the vertical direction is increased appreciably by providingthe shoulder portions 56 and the pressing portions 58.

[Table 1] TABLE 1 with shoulder without shoulder portions, portions,pressing portions pressing portions Vertical front-back verticalfront-back 155 125 145 125(unit: N/mm)

By being able to adjust spring constant in this way, spring constant inthe rubber elastic body 16 can be increased in the past to the optimalspring constant to enable easy tuning.

The embodiment of the invention set forth in detail hereinabove ismerely exemplary, with various modifications being possible withoutdeparting from the spirit of the invention.

1. An engine mount for a vehicle comprising: an upper rigid memberfixable to an engine side; a lower rigid member fixable to an vehiclebody side; a rubber elastic body elastically connecting the upper andlower rigid members; and a rigid stopper member of overall bridgeconfiguration having a pair of leg portions situated at front and backand a bridge portion linking these leg portions in a front-backdirection of the vehicle above the rubber elastic body, wherein therubber elastic body has a front-back dimension of an upper half thereofsmaller than that of a lower half thereof; the upper half constitutes afront-back direction rubber stopper portion opposed to and spaced apartfrom the pair of leg portions of the bridge shaped stopper member in thefront-back direction by a stopper clearance; the bridge shaped stoppermember is press fitted onto and attached to the rubber elastic body andthe lower rigid member by being assembled through an opening of a lowerend thereof, with the lower half clamped elastically between the pair ofleg portions; a rigid bracket for linking the upper rigid member to theengine side is integrally formed on the upper rigid member, with therubber elastic body supporting the bracket in a cantilever fashion sothat an engine secured fastened to the bracket being supported in asuspension fashion; the upper rigid member and the lower rigid memberare integrally vulcanization bonded to the rubber elastic body; a pairof shoulder portions of step configuration projecting in the front-backdirection from an upper end of the lower half are disposed at front andback on the rubber elastic body, while downturned pressing portions ofstep configuration are disposed at corresponding front and backlocations on the bridge shaped stopper member; and with the stoppermember being press fitted onto the rubber elastic body and the lowerrigid member, the pressing portions of the stopper member pressdownwardly the shoulder portions of the rubber elastic body causingcompression deformation of the lower half, producing a state of fixationof the lower half to the stopper member.
 2. An engine mount according toclaim 1, wherein each of the shoulder portion has a shape prior toattachment of the stopper member, in which a portion that contacts thepressing portion includes an upwardly projecting convex portion at anouter portion thereof in the front-back direction, and a relativelydownward facing concave portion at an inner portion thereof.
 3. Anengine mount according to claim 2, wherein the pressing portion has ashape that presses the upwardly projecting convex portion until theconvex portion is rendered non-convex by means of attachment.
 4. Anengine mount according to claim 1, wherein each of the shoulder portionsis formed over an entirety of a width direction of the rubber elasticbody which is a left-right direction of the vehicle, and each of thepressing portions is formed as a pair of pressing portions located atopposite ends in a width direction of the stopper member, with a portionlying between the pair of pressing portions at the opposite ends in thewidth direction being constituted as a reinforcing rib.
 5. An enginemount according to claim 1, wherein in the rubber elastic body, portionsextending from front and back stopper faces down to front and backcontact faces of the lower half against the stopper member arecontinuous with contact faces without creating a constricted portion inthe front-back direction at midpoint.
 6. An engine mount according toclaim 1, wherein portions of the lower rigid member that are opposedvertically to the pressing portions are formed as upturned convexportions.
 7. An engine mount according to claim 6, wherein each of theupturned convex portions of the lower rigid member includes in anoutside of a vertex thereof in the front-back direction, a pressuresurface extending towards an inside surface of the leg portion opposedthereto as it goes downward, and the corresponding shoulder portion ofthe rubber elastic body is configured so as to extend toward the insidesurface of the corresponding leg portion beyond the vertex.
 8. An enginemount according to claim 7, wherein the shoulder portions of the rubberelastic body have the upturned convex portions at their most outerperipheral edge portions in the front-back direction.
 9. An engine mountaccording to claim 6, wherein the convex portions of the lower rigidmember are embedded within an interior of the lower half of the rubberelastic body, and exerts restraining action from an interior of therubber elastic body against portions of the lower half clamped by thestopper member.
 10. An engine mount according to claim 9, wherein theconvex portions of the lower rigid member have straight shaped portionsthat rise straight along the leg portions in the bridge shaped stoppermember, with thin rubber layers constituting part of the rubber elasticbody being formed between the straight shaped portions and the legportions, respectively.
 11. An engine mount according to claim 1,wherein an entire fastener portion to the rubber elastic body of thelower rigid member is embedded within the rubber elastic body, with arubber underlayer constituting part of the rubber elastic body beingformed below the lower rigid member.